1. Field of the Invention
The present invention relates generally to magnetic pole tip configurations for magnetic write heads, and more specifically to pole tip configurations that reduce magnetic side writing.
2. Description of the Prior Art
For very high density magnetic recording it is necessary to record magnetic domains very close together. The bit packing is done in both the linear direction (Bits per Inch (BPI)) and in the radial direction (Tracks per Inch (TPI)). The TPI is generally determined by two parameters, the size of the written bit that is primarily determined by the second pole tip""s lateral dimension (P2W), and the inter-track guard band that is mostly composed of magnetic noise. The width of the inter-track band is determined by how well the drive can servo, the accuracy of the actuator system, and by the extent of the side writing of the poles. The side writing is one of the easier parameters to control, and reduce, because it is an intrinsic function of the way pole tips are constructed.
To reduce side writing, pole tips of various shapes have been developed, such as rectangular and trapezoidal shapes. Additionally, write heads have been developed that include a notched first pole tip, as described in U.S. Pat. No. 5,901,432, in an effort to reduce sidewriting. As the width of the base of the P2 pole has been reduced, in order to produce narrower track widths, the effect of side writing has become more pronounced in relation to the narrowed track widths. The side writing produced by the P2 pole tips therefore requires further reduction, and the P2 pole tip of the present invention, with its negative profile, provides such a side writing reduction.
The magnetic writing head of the present invention includes a P2 pole tip having a novel profile. This profile, as viewed from the air bearing surface (ABS) can generally be described an hour glass shape in that the minimum width of the pole tip is disposed away from the base of the P2 pole tip. The negative profile results in a significant reduction in magnetic side writing that emanates from the write head.
A novel method for producing the negative profiled pole tip involves control of the photoresist processing parameters and pole tip plating parameters. Specifically, the photoresist is baked at particular temperatures for particular periods of time, such that the cross linking within the photoresist is produced to the extent that the photoresist will controllably swell during the plating operation. The result is that as the P2 pole tip is plated, the photoresist swells to cause the negative profile along the thickness of the pole tip.
It is an advantage of the present invention that a magnetic write head has been developed that produces reduced magnetic side writing.
It is another advantage of the present invention that a magnetic pole tip has been developed that produces reduced side writing with no additional manufacturing steps over the existing manufacturing methods.
It is a further advantage of the present invention that an improved magnetic write head has been developed that is simple to manufacture.
It is yet another advantage of the present invention that the manufacturing method for a magnetic write head has been developed which produces an improved write head with no additional manufacturing steps.
These and other features and advantages of the present invention will become well understood by those skilled in the art upon reading the following detailed description which makes reference to the several figures of the drawings.